Study on Progressive Failure of Hard Rock Tunnel After Excavation Under High Stress

Figure 6

The evolution of cracks in PD62-2: (a) 825100, (b) 826100, (c) 827100, (d) 828100, (e) 829100, (f) 830100, (g) 831100, (h) 832100, (i) 833100, (j) 834100, and (k) 835100.

(a)

(b)

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(e)

(f)

(g)

(h)

(i)

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(k)